feat: add auto-merge configuration for Dependabot PRs

[bednar]

Proposed Changes

This pull request introduces improvements to Dependabot automation and makes a minor fix to the CircleCI workflow configuration. The most significant changes are the addition of an auto-merge workflow for Dependabot PRs and expanding Dependabot update coverage to GitHub Actions.

Dependabot Automation Enhancements:

• Added a new GitHub Actions workflow (.github/workflows/dependabot-auto-merge.yml) to automatically approve and enable auto-merge for Dependabot pull requests, streamlining dependency updates.
• Updated .github/dependabot.yml to include the github-actions ecosystem, ensuring that GitHub Actions dependencies are checked and updated by Dependabot.

CI Configuration Fix:

• Fixed a syntax issue in the python-image matrix parameter in .circleci/config.yml by quoting the cimg/python:3.13 image, ensuring consistent parsing in the workflow.

Checklist

• Rebased/mergeable
• Tests pass
• Commit messages are conventional
• Sign CLA (if not already signed)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.20%. Comparing base (37cf75a) to head (ab32a9b).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #187   +/-   ##
=======================================
  Coverage   70.20%   70.20%           
=======================================
  Files          35       35           
  Lines        2356     2356           
=======================================
  Hits         1654     1654           
  Misses        702      702           

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